Express your answer as a mixed number simplified to lowest terms. $7\dfrac{7}{9}-6\dfrac{1}{9} = {?}$
Separate the whole numbers from the fractional parts: $= {7} + {\dfrac{7}{9}} - {6} - {\dfrac{1}{9}}$ Bring the whole numbers together and the fractions together: $= {7} - {6} + {\dfrac{7}{9}} - {\dfrac{1}{9}}$ Subtract the whole numbers: $=1 + {\dfrac{7}{9}} - {\dfrac{1}{9}}$ Subtract the fractions: $= 1+\dfrac{6}{9}$ Combine the whole and fractional parts into a mixed number: $= 1\dfrac{6}{9}$